Every so many years, there arrives a windstorm that
seems like a contender for challenging the great Columbus Day storm of 1962
for "largest wind event on record." Such blows include, but are
not limited to March 26-27, 1971, November 14, 1981, and January
20, 1993. Though there has often been a lot of dramatic press coverage
about such storms--with some good reason, as they were fairly powerful,
even life-threatening, events--none of these windstorms have matched the
grandeur of Columbus Day 1962. None.

December 11-12, 1995, saw the development of yet another contender for
top storm, a low that "bombed" (a slang term for explosive
cyclogenesis, which is when a low pressure center deepens rapidly) off
of the California coast, then tracked northeast-ward up the west coast into
Washington, blasting towns and cities all the way up the U.S. West Coast.
This storm almost matched the Columbus Day storm peak gust for peak gust
along the immediate coast, and even exceeded it in select regions, like
in the San Francisco Bay Area. But further north, the December 1995 storm
didn't reach the strength of the Columbus Day blow in the Willamette Valley
and in the Puget Lowlands. For Oregon, the lower wind velocities were partly
due to the fact that the December 1995 storm generally did not track as
closely to the coast as did the 1962 "Big Blow." The Columbus
Day Storm hugged Oregon's Coast at a distance of 50-75 miles, starting from
the southern border all the way up, heading in a generally northward track.
The December 1995 storm started much further offshore of SW Oregon and raced
northeastward, as an excerpt from this report issued at 9:45 PM PST Monday
December 11, 1995 suggests: "Satellite imagery and ocean buoy reports
confirm the development of an intense low pressure center 600 miles off
the coast of Oregon. Forecast models continue to show the low moving northeast
along the coast and into northwest Washington by Tuesday evening."
Another report at 12:15 PM PST Tuesday December 12, 1995 reads: "At
12 Noon the intense storm was located about 100 miles west of Astoria Oregon
and was moving northeastward towards the extreme northwest tip of Washington.
By 4 PM PST it should be near Tatoosh Island."

The greater distance offshore appears have been the big factor that prevented
the kind of terrific gale seen in 1962 from striking Oregon. This can't
be the reason why much of Western Washington was spared a Columbus-Day-like
gale. After the 1995 cyclone passed the latitude of Astoria, it finally
did come within a distance equal to the 1962 storm. A report from
the NWS Seattle issued at 2 PM PST Tuesday December 12, 1995 mentions: "At
2 PM...The intense storm was located about 50 miles northwest of Astoria
Oregon and moving northeast. The storm center is now expected to move across
the Olympic Peninsula by 5 PM." The low did cross the Olympic Peninsula,
putting the 1995 center much closer to many Western Washington locations
when compared to the 1962 center. Stronger winds can expected nearer the
center, where the steepest gradients often reside. Yet these locations didn't
suffer winds any higher than places in Oregon. It appears that the December
1995 low was a bit broader than the Columbus Day Storm, with gradients not
quite as dramatic. One indicator of this is with the Astoria-Hoquiam (AST-HOQ)
measure of pressure gradient. The December 12, 1995 windstorm produced a
peak AST-HOQ gradient of +8.6 mb (+0.25") at 19:00 as the low moved
ashore just north of Hoquiam. The Columbus Day Storm produced a peak AST-HOQ
gradient of +10.8 mb (+0.32") at 21:00 as the low scooted by just offshore.
Due to the difference in tracks, the December 1995 storm was favored
for a maximal gradient when compared to the Columbus Day Storm. That the
Columbus Day Storm managed 2.2 mb higher than the 1995 event with less favorable
low-center orientation suggest a more tightly wound cyclone in 1962.

One other factor probably contributed to lower wind speeds throughout
Western Oregon and Washington on December 12, 1995: storm speed. The Columbus
Day Storm moved more rapidly than the 1995 event, and this difference could
have contributed to the higher wind speeds witnessed in the earlier storm.

Figure 1, below, was found on a San Francisco State University
website on this storm: Explosively
Developing Cyclone. This image was taken at 04:00 PST, just as the winds
were beginning to escalate in the San Francisco Bay Area. The exact center
of the low is northeast of the tip of the bent-back occlusion. The core
was rather elongated to the northeast, and was showing some signs of developing
a secondary center right off of Northwest Oregon.

From the few datapoints available, it seems that most of the big 955
to 975 mb cyclones that follow northward tracks close to the U. S. West
Coast ("Inside 130", as NWS forecasters like to say, which referrs
to east of 130º W longitude) tend to produce maximum wind gusts of
about 60 to 95 mph at offical stations on the coast and 50 to 75 mph at
official stations inland. This is the standard scenario. This is generally
what happened during the large events in October 1950, March 1971, November
1981, and during the December 1995 storm examined on this web page. Peak
wind velocity among these storms, and other lesser events, varies with a
rough correlation to minimum central pressure.

The Columbus Day Storm was different. It's minimum central pressure of
about 960 mb wasn't that unusual among the big cyclones. December 1995 was
deeper. However, the Columbus Day winds were unusual. Gusts reached about
80 to 140 mph at official stations on the Oregon coast, and 85 to 125 mph
at stations inland. This makes the Columbus Day Storm an outlier. It is
off-the-curve unique. A singularity. An event like the Columbus Day Storm
probably won't happen again for another 100 years, maybe even 1,000. The
Columbus Day Storm probably should be treated as its own category--especially
when trying to forecast the peak wind potential of a new cyclogenic bomb
based on windstorm climatology.

Figure 1, below, depicts the track that the December 12,
1995 cyclone followed. The 1995 low continued to deepen as it moved northward,
somewhat unlike the Columbus Day Storm, which reached peak intensity off
the Oregon Coast, and then slowly degraded as it raced northward.

Personal Experience

What follows is what I recorded in my journal during the December 1995
windstorm, with some notes on damage seen some time after the event. Keep
in mind that, at the time, I lived in El Cerrito, a small incorporation
on the east shore of the San Francisco Bay. This put me in the center of
a region that saw windspeeds that challenged the Columbus Day Storm:

December 12, 1995: Tuesday

08:45 HRS: (El Cerrito, CA) BIG storm this morning. After months of dry--very
little rain since June 20! five-and-one-half months of sun and fog--a couple
of major storms have finally broken through the monotony. The first--yesterday--dumped
a lot of rain on us: 3.5"+ in SFO, up to 7.0" in some regions.
Following this rain, a strong low has moved toward the coast north of us.
Our pressure is 29.62" and steady now (the low has stalled). This storm
center has been swinging in solid bands of moisture, as well as kicking
in winds of 50-75 mph at the surface throughout the Bay Area. Our power
is out, along with 300,000 homes in the PG&E district. Trees are down
all over. One fell on a minivan, crushing it. Two blocked an onramp to the
Golden Gate Bridge near Presidio. One park, I'm guessing the Presidio, reported
72 trees down. Roofs are flying off as well. A carport shed its top and
dropped it across 4 southbound lanes and 2 northbound lanes of 101 [south
SF peninsula]. I also heard a report of a condo losing its roof, and a restaurant
in SFO. Flooding is prominent as well: HWY-17 has lanes flooded, 280 in
Daly City, other roads as well (Highway 4 yesterday). The Bay Bridges were
closed earlier, and are now open to car traffic--no trucks or campers. This
is a major storm. Another is coming in. It may not be as windy, but is expected
to dump more heavy rain on top of ground saturated already, so the weather
service is saying the next storm is extremely dangerous. Latest report:
Still 300,000 homes without power, unofficial report of 90 mph gusts near
Eureka. I'd say we've been gusting to 60 mph locally--some of the gusts
were loud hitting the building and shook the place enough to feel like an
earthquake. I had the flashlight standing on its broad light-end fall over
in one gust (4-cell Maglite). Needless to say, I'm staying home from work
(though I may go in later, but I doubt it).~0910 HRS.

20:30 HRS: Our power finally got restored at 20:00! Thirteen hours w/o
power! The absurdity is that houses only block away had power. Home on the
small rise to the west glowed, as well as on Albany Hill. Homes to the north
by one block also had power.

I haven't seen any news yet, so haven't been able to catch up on the
damage from the morning's gale. I will note that a radio tower blew over
on San Bruno mountain, knocking out the station that I was listening to
at the time (07:03~). Many roofs flew from various locals, and San Francisco's
high rises shook and swayed so much that in one instance a Christmas tree
on the top floor fell over.

The storm ripped all the way up the West Coast, hitting west Oregon hard,
Washington with a vengeance: Shelton: 80 mph, Auburn 70 mph, Seattle 60
mph, Everett 46 mph, Alkai Pt. 52 mph so far with gusts to 100 mph on Washington's
coast. I got this from my Dad, whom I just talked to on the phone. The storm
had just started up there, so it looks like they'll be in for a fun night.

A note: our peak winds were in the 70-75 mph range with locally higher
gusts, though I think our highest winds here in El Cerrito were 55-60 mph
(70+ at SFO airport). Areas of highest damage include Redwood City and Pleasant
Hill. This is all I can say, 'cuz I'm still trying to get the TV/VCR to
work so I can see the news. And my hand is tired (been drawing all day).
~2050 HRS.

December 13, 1995: Wednesday

20:57 HRS: (El Cerrito, CA) I've read a bunch of official stuff on the
storm of yesterday. Peak gust of 85 mph at SFSU, 75 mph at Alameda Naval
Base in Oakland, 70 mph at SFO [upgraded to 74 mph, I believe]. These are
just a few: 103 mph at Angel Island was another noteworthy peak (wow!!!).
Two people died in the Bay Area from trees falling on their houses, one
from a tree smashing their car. Two 230,000 volt transmission towers were
toppled in the South Bay (PG&E owned, of course). The San Francisco
conservatory was severely damaged structurally, and plants inside suffered
greatly, all to the tune of $10,000,000 dollars. The SF Zoo's aviary also
suffered losses. Other noteworthy weather events include 2.66" of rain
in 45 minutes at the Alameda Naval Station. Up to 15.01" of rain fell
at Russian River Sunday night to Tuesday, 5.33" at SFO, 5-9" in
many North Bay locations Oakland up and over 12" at Saulsalito. We
certainly made up for the lack of rain in October and November. Sacramento
lost many trees and had powerlines down all over, yet fortunately had no
fatalities.

We were slapped hard, but some of the most amazing stuff happened in
Western Washington. The low trekked across the Olympic Peninsula from my
understanding, and pressures dropped to 958 Mb at Ellis (-I'll have to check
this) Island!! [This reading was for the Cape Elizabeth buoy, actually.]
What's more amazing is that SeaTac Airport dropped to 970 Mb (28.65")
as the low passed! Read: 28.65--I'm shocked. That's about what Astoria dropped
to in the great Columbus Day storm of 1962, and it happened far inland nontheless.
I'd've never guessed that SEA would achieve so near a record established
on the coast! What a storm. However, winds at SEA weren't so impressive,
gusting to only 47 mph by the data I have. Other places reached higher,
upwards of 59 in Olympia, 52 in Bellingham, 60 at Bremorton, 80 (as mentioned)
in Shelton, 78 in North Bend, WA, North Bend, OR, hit 107 mph! (But not
achieving the 138 mph recorded in the Columbus Day storm [confused with
Newport!]) many coastal locales in Oregon hit between 90 and 110 (even 112)
mph. [Portland peaked at 62 mph.] Spokane, WA, did not escape, hitting a
damaging 74 mph. WA did not get the heavy rain of CA, though, in this storm.

January 28, 1996: Sunday

Today, Silven and I hiked up the meadow, and through the surrounding
woods with the Zuidema's two golden retrievers Rascal and Charlie, who usually
go on these walks with me. I was scouring the forest [in Scotts Valley,
CA] for wind damage from the December 12 windstorm. Their [the Zuidema's]
power had been knocked out for 4 days from that storm, so I had expected
to see much damage in the forest which I had hiked so much. No such thing.
I could hardly find felled branches, let alone fallen trees. My hiking grounds
appeared to have been spared any major damage. Until I reached the saw mill.

One of the huge redwoods that was a member of the small grove which surrounded
the saw mill had its tip broken many years ago. As a result, it for two
growth tips and continued its extension into the sky. One tip, the one on
the south side, was smaller than the north tip. The north tip grew to a
vast size, one that would have made a healthy-sized tree in its own right.
During the great windstorm of 1995, the north tip, shearing down a plane
of weakness undoubtedly as old as the tip itself, snapped clean off. Dropping
its massive 50' + length over easily 75-100' of space, the tip smashed the
lumber, or saw, mill into a pile of broken plastic roof and 2x4s, all buried
under the shattered branches of the redwood trunk and all the other trees
the failed tip brought with it on its plummet earthward. The mill was gone,
smashed out of existence, buried by a single blow.

This, the only tree to break in the area for quite some distance around.
Near an orchard being reclaimed by the local wildlife, such as lizards and
snakes, and trees of every description. A single redwood, breaking, burying
the saw mill with its cascade of wood and green needles. Another victory
for a little understood world. 2020 HRS.

February 19, 1996: Monday (Holiday!)

18:21 HRS (Home, Martinez, CA) Ha! Sitting by a fire (Duraflame) after
a strong storm blew through, dumping heavy rain and producing 20 to 40 mph
wind gusts. At least two more storms are expected in the next few days,
fronts swinging under a strong semipermanent low offshore to the NW. The
next one, due Tues night is expected to be very strong, and also the coldest
storm of the season so far. We've already had the lowest barometer thusfar
at 29.52" of so (lowest for winter), with the last low at 29.60"
in the Dec 12, 1995 windstorm.

Speaking of that storm, Silven and I drove out to the Bay Area Discovery
Museum today, in the driving--at one time blinding on Highway 101 north--rain
and gusty wind. A number of large trees had been blown down by the Dec 12
storm there in a forest alongside a hill on the west part of the [BADM]
grounds, and in the US Coast Guard area. One spot, right at the base of
the steep hill near the road, had a swath of, say, 20-25 trees blown over--a
near total flattening, and a rare sight, though I only saw the stumps, for
the boles had been sawed away, and it looked like a few trees in the swath
hadn't been uprooted, but there was no way, of course, to see if they had
been topped by the gale. Near the swath, which left the remaining stand
of cypress looking very toothpickish and bare with just green leaves and
branches at their top (light competition), a eucalyptus had also fallen
and damaged the roof and wall of a USCG warehouse-like building. Quite a
sight. I'd say the wind probably gusted in the 85-90 mph range there, maybe
enhanced by the hill's aerodynamics-->it is notable that only that small
area had near total treefall while many exposed trees did not fall or suffer
major damage.

General Storm Data

Minimum Pressures and Peak Gradients

Table 1, below, lists the lowest barometric pressure readings
at various locations in the December 12, 1995 windstorm, and the Columbus
Day Storm and compares them, when available. The readings for the December
1995 storm are spectacularly low. Note that Salem in 1995 dropped as low
as did Tatoosh Island in 1962! The Columbus Day low-pressure center was
beginning to fill significantly as it headed into the waters off of Washington.
The lowest central pressure for the storm of 1962 was about 28.30"
at 11:00 AM, when the low was 205 miles west of Eureka, CA (this information
comes from Franklin, Dorothy, "West Coast Disaster," 1962).
It seems that the December 1995 low didn't undergo much filling before making
landfall on the Olympic Peninsula. Maybe the difference in tracks allowed
the 1995 low to maintain integrity as it raced inland. After all, the Columbus
Day Storm spent a large part of its existence close to shore, and the degrading
effects of the vertical topography of the west. The December 1995 low, on
its northeast track, didn't get very close to land until it had reached
the latitude of Washington.

There's a nice trend of increasing difference in barometric minimums
in a northward direction, from about 0.10" in Northern California to
about 0.30" in Northern Washington, with some exceptions (like Toledo).
This reflects on the December 1995 storm's northeast tendency compared to
the Columbus Day Storm's northward migration. Washington stations, in general
were much closer to the center of action in 1995. The Columbus Day Storm's
weakening offshore of Washington also contributed.

[1] The 1995 value (958.8 mb) is from Buoy 46041 Cape Elizabeth, 52 miles
west of Aberdeen, WA. From the National Data Buoy Center historical
meteorological data.

[2] The 1995 figure is from the Destruction Island C-MAN station, and
was obtained from the National Data Buoy Center historical meteorological
data. The 1962 figure is from Decker, Fred W., Cramer, Owen P., Harper,
Byron P, "The Columbus Day 'Big Blow' in Oregon," Weatherwise,
December 1962.

[3] The 1995 figure is from the Tatoosh Island C-MAN station, and was
obtained from the National Data Buoy Center historical meteorological
data.

[3] Sadly, the unedited surface observation forms for some stations during
the December 12, 1995 windstorm are lost due to a corrupt data file at the
NCDC. This includes Quillayute, Seattle, Medford and San Francisco. The
minimum reading from Seattle is from the NCDC Storm Data publication for
December 1995.

Table 2, below, lists the lowest barometric pressures achieved
during the December 12, 1995 storm for the 11 key Pacific Northwest locations
used in general comparison between storms on this website, and the time
of occurrence of the barometric minimums. Many of these values are all-time
record low pressures, including the readings at Arcata, Bellingham, Eugene,
Olympia, Salem and Seattle. The minimum of 28.53" (966.1 mb) at Astoria,
often noted as the all-time low pressure for that location, was short of
the 28.45" (963.4 mb) reading witnessed durng the Storm King of Janaury
9, 1880. Portland's reading of 28.73" (973.0 mb) is at least third
place, being short of the 28.72" (972.6 mb) reading from the great
December 4, 1951 windstorm and the 28.56" (967.2 mb) reading from the
January 9, 1880 event. At North Bend, the low pressure of 28.70" (971.9
mb) during the Columbus Day Storm was slightly lower than the 28.72"
(972.6 mb) during the 1995 gale.

At Tatoosh Island, the barometric pressure was at or below 28.75"
(973.5 mb) from the 06:00 observation to 20:00, an incredible 14 hours!
At Seattle, pressures held at or below 28.75" from 12:00 to 19:00,
or seven hours. The long period of low pressure, plus the close association
in time of pressure minimums at Western Washington locations, mark a very
deep, broad low, one that appears to have been elongated in an west-to-east
manner.

The average minimum pressure of 28.69" (971.6 mb) for these stations
is significantly lower than the 28.85" (977.0 mb) 11-station average
for the Columbus Day Storm, and the 28.90" (978.7 mb) average for the
December 4, 1951 cyclone. The December 12, 1995 cyclone produced the lowest
pressure minimum average out of any cyclone to strike the Pacific Northwest
in the 1950-to-present era.

Source: Pressure data is from the National Climatic Data Center,
Unedited Surface Observation Forms (most stations), and the National
Data Buoy Center historical meteorological data (Tatoosh Island C-MAN
station TTIW used in place of Quillayute, and West Point C-MAN station WPOW1
used in place of Sea-Tac).

Location

Lowest
Pressure

Approx Time
of Lowest Pressure

California:

Arcata

29.05"

06:00 HRS, 12th

Oregon:

North Bend

28.72"

08:00 HRS, 12th

Astoria

28.53"

13:00 HRS, 12th

Medford [1]

MM

MM

Eugene

28.77"

09:00 HRS, 12th

Salem

28.73"

12:00 HRS, 12th

Portland

28.73"

13:00 HRS, 12th

Washington:

Quillayute [2]

28.49"

15:00 HRS, 12th

Olympia

28.61"

15:00 HRS, 12th

Seattle [3]

28.63"

14:00 HRS, 12th

Bellingham

28.63"

15:00 HRS, 12th

AVERAGE [4]

28.69"

Table 2, notes.

[1] Medford's unedited surface observation forms lost due to a corrupt
data file at the NCDC.

[2] Quillayute's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Tatoosh Island C-MAN station TTIW used in place of
Quillayute.

[3] Sea-Tac's unedited surface observation forms lost due to a corrupt
data file at the NCDC. West Point C-MAN station WPOW use in place of Sea-Tac.

[4] Due to missing data from Medford (see [1] above), the average in
the case of the December 12, 1995 storm is from the ten available samples.

Table 3, below, is a list of the maximum hourly pressure
gradients, and time of occurrence, for the December 12, 1995 windstorm.
Some of these measures are spectacular. The ACV-AST value of +33.0 mb (+0.97")
ties the peak value for the Columbus Day Storm. The OTH-UIL reading of +31.8
mb (+0.94") beats the peak value of +27.3 mb (+0.81") witnessed
during the Columbus Day Storm by a decisive margin. The Columbus Day Storm
was clearly weakening as it moved into Washington's offshore waters, and
this may account for the lower OTH-UIL (TTI) gradient for the 1962 event.
The peak PDX-SEA gradient of +15.3 mb (+0.45") is second only to the
+15.4 mb (+0.455") value generated by the Inauguration Day storm of
1993, and is significantly above the +9.9 mb (+0.29") peak value for
the Columbus Day Storm--though it should be kept in mind that the PDX-SEA
reading in December 1995 is actually a PDX-WPOW (West Point) reading, which
is over a longer distance and therefore probably a millibar or two high
when compared to the standard PDX-SEA measure.

Source: Pressure data is from the National Climatic Data Center,
Unedited Surface Observation Forms (most stations), and the National
Data Buoy Center historical meteorological data (Tatoosh Island C-MAN
station TTIW used in place of Quillayute, and West Point C-MAN station WPOW1
used in place of Sea-Tac).

Location

Max Gradient, mb

Approx Time
of Max Gradient

Coast:

ACV-OTH

16.6

10:00 HRS, 12th

OTH-AST

22.6

16:00 HRS, 12th

AST-UIL [1]

18.3

20:00 HRS, 12th

ACV-AST

33.0

15:00 HRS, 12th

OTH-UIL [1]

31.8

18:00 HRS, 12th

Interior:

MFR-EUG [2]

MM

MM

EUG-PDX

9.1

16:00 HRS, 12th

PDX-SEA [3]

15.3

19:00 HRS, 12th

SEA-BLI [3]

8.7

21:00 HRS, 12th

AST-DLS [4]

-14.1

06:00 HRS, 12th

Table 3, notes.

[1] Quillayute's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Tatoosh Island C-MAN station TTIW used in place of
Quillayute. Incidentially, this makes for more accurate comparisons between
this storm and those before the 1964 opening year for the Quillayute station,
which replaced the Tatoosh station for many decades.

[2] Medford's unedited surface observation forms lost due to a corrupt
data file at the NCDC.

[3] Sea-Tac's unedited surface observation forms lost due to a corrupt
data file at the NCDC. West Point C-MAN station WPOW use in place of Sea-Tac.
The different positions of SEA and WPOW probably cause the PDX-WPOW gradient
to be about 1-2 mb high and the WPOW-BLI 1-2 mb low when compared to the
standard PDX-SEA and SEA-BLI measures.

[4] Sea-level pressure unrecorded at The Dalles from 23:00 to 05:00 each
day. The peak gradient listed, having occurred right at the first DLS observation
of the 12th, could have been higher before 06:00.

Pressure Tendencies

Table 4, below, lists the maximum hourly pressure falls
and rises achieved during the December 12, 1995 storm for 11 Pacific Northwest
stations. The peak -5.1 mb (-0.15") hourly drop at North Bend is the
highest on record, slightly beating out the -5.0 mb (-0.148") recorded
as the great Columbus Day Storm raced northward toward the station. The
rest of the values, both in fall and rise, are quite strong, but other storms
in history have exceeded these tendencies--in some cases by a large margin.
In terms of the 11-station averages, the Columbus Day Storm was clearly
ahead of the December 12, 1995 event on both counts with a -4.6 mb (-0.14")
average hourly declension, and a +6.2 mb (+0.18") average hourly climb.
The -3.5 mb (-0.10") average for the December 12, 1995 storm is behind
at least five storms in the 1950-to-present era: November 14, 1981 (-3.7
mb / -0.11"), October 12, 1962, December 16, 1961 (-3.6 mb / -0.105"),
December 21, 1955 (-4.1 mb / -0.12") and December 4, 1951 (-4.4 mb
/ -0.13"). And the +4.5 mb (+0.13") average for the 1995 storm
is behind at least three storms in the 1950-to-present era: October 12,
1962, December 20, 1961 (+4.6 mb / +0.136") and February 24, 1958 (+5.2
mb / +0.15" based on eight stations).

Some of the more spectacular pressure surges during the December 12,
1995 windstorm happened at buoys and automated stations along the Washington
shoreline as the bent-back occlusion pushed inland behind the low center.
At Destruction Island, starting at 20:00 on December 12th, the pressure
surged from 972.3 mb (28.71") to 979.3 mb (28.92") in a single
hour--that's +7.0 mb (+0.21"). At the time of the pressure jump, strong
west-southwest winds poured in, sustaining at 62 mph and gusting to 70.
Buoy 46041 Cape Elizabeth witnessed a +6.0 mb (+0.18") surge during
the same hour, with southwest winds escalating to 43 mph gusting to 58.

Welcome to the Information Age, era of twitchy machines. The ever-familiar
corrupt data files from the NCDC for the MFR, SEA and UIL stations turns
up here, with missing and or substituted values.

Source: Pressure data is from the National Climatic Data Center,
Unedited Surface Observation Forms (most stations), and the National
Data Buoy Center historical meteorological data (Tatoosh Island C-MAN
station TTIW used in place of Quillayute, and West Point C-MAN station WPOW1
used in place of Sea-Tac) and for the Destruction Island and Cape Elizabeth
descriptions.

Maximum Pressure Tendencies for the December 12, 1995
Storm

Location

Max
Hrly
Fall
mb

Time of
Max Fall
PST

Max
Hrly
Rise
mb

Time of
Max Rise
PST

California:

Arcata

-3.7

19:00 HRS, 11th

+4.8

09:00 HRS, 12th

Oregon:

North Bend

-5.1

22:00 HRS, 11th

+3.3

16:00 HRS, 12th

Astoria

-3.7

01:00 HRS, 12th

+5.7

18:00 HRS, 12th

Medford [1]

MM

MM

MM

MM

Eugene

-3.8

23:00 HRS, 11th

+3.7

16:00 HRS, 12th

Salem

-3.2

02:00 HRS, 12th

+4.0

17:00 HRS, 12th

Portland

-3.2

00:00 HRS, 12th

+3.7

17:00 HRS, 12th

Washington:

Quillayute [2]

-3.3

04:00 HRS, 12th

+5.2

22:00 HRS, 12th

Olympia [3]

-2.8

01:00 HRS, 12th

+5.4

20:00 HRS, 12th

Seattle [4]

-3.2

06:00 HRS, 12th

+4.3

21:00 HRS, 12th

Bellingham

-3.2

04:00 HRS, 12th

+4.8

23:00 HRS, 12th

AVERAGE [5]

-3.5

+4.5

Table 3, notes.

[1] Medford's unedited surface observation forms lost due to a corrupt
data file at the NCDC.

[2] Quillayute's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Tatoosh Island C-MAN station TTIW used in place of
Quillayute. Incidentially, this makes for more accurate comparisons between
this storm and those before the 1964 opening year for the Quillayute station,
which replaced the Tatoosh station for many decades.

[3] The -2.8 mb/hr drop is the first of two occurrences, the other being
at 02:00 on the 12th.

[4] Sea-Tac's unedited surface observation forms lost due to a corrupt
data file at the NCDC. West Point C-MAN station WPOW use in place of Sea-Tac.

[5] Due to missing data from Medford (see [1] above), the average in
the case of the December 12, 1995 storm is from the ten available samples.

Peak Wind and Gust

Table 5, below, provides a list of peak gusts from the
December 1995 windstorm, and the Columbus Day Storm of 1962, so that the
two storms can be compared. I also offer the difference in the peak gust
speeds, and what that means in terms of wind force (i.e. the difference
in the strength of the wind, as opposed the velocity). Wind
force increases with the square of the velocity. In other words, when the
velocity is doubled, the force is quadrupled. A 50 mph wind at sea level
produces about 10 lbs per square foot of force. A 100 mph gust hits with
four times the force--about 40 lbs per square foot, not 20 as one might
suppose by simply doubling the force in correspondance with the increase
in velocity. By examining the peak gusts in this light, we see that the
Columbus Day Storm had significantly more punch than the December 1995 windstorm
in many areas. Sources include the National Climatic Data Center
(such as the Local Climatological Data, Unedited Surface Observation Forms,
and online Climate Visualization Database), the National Weather Service
at Portland (such as the online monthly summaries for Eugene, Salem
and Portland) and Seattle (For example, Bellingham's peak gust was
mentioned in a High Wind Warning Statement issued at 12:12 AM PST Wednesday
December 13, 1995), and Franklin, Dorothy, "West Coast Disaster,"
1962. Some of the figures below are tentative, and could be changed
as I find more information on these two storms. Interestingly, for North
Bend, OR, neither of these storms were the strongest in the past 40 years--November 1981 saw a gust to 92 mph at this
location!

Location

Dec 1995
Peak (mph)

Oct 1962
Peak (mph)

Difference
(mph)

Force Difference (number of times difference in strength of peak gust,
with year of strongest storm listed).

California:

San Francisco

74

63 [3]

+11

1.38 X (1995)

Erueka/Arcata

64

58

+6

1.21 X (1995)

Redding/Red Bluff

85

81

+4

1.10 X (1995)

Crescent City

59

69

-10

1.37X (1962)

Oregon:

Coast:

North Bend

86

81

+5

1.13 X (1995)

Newport

107

138

-31

1.66 X (1962)

Astoria

62

96

-34

2.40 X (1962)

Willamette Valley:

Eugene

49

86

-37

3.08 X (1962)

Salem

59

90

-31

2.33 X (1962)

Portland

62 / 74 [1]

104 [1]

-30

1.98 X (1962)

Washington:

Coast:

Hoquiam

69

81

-12

1.38X (1962)

Quillayute

43

N/A

Tatoosh Island

61

78

-17

1.63X (1962)

Interior:

Toledo

67

89

-22

1.76X (1962)

Olympia

66

78

-12

1.40 X (1962)

Sea-Tac Airport

60

58 [3]

+2

1.07 X (1995)

Bremorton

60

75

-15

1.56 X (1962)

Everett

64

81 [2]

-17

1.60 X (1962)

Bellingham

76

98

-22

1.66 X (1962)

Table 5, notes.

[1] 62 mph is from the ASOS system. Apparently peak gust recorders registered
74 mph (source, National Weather Service, Portland, "Climate
of Portland." This is also the source for the peak gust of
104 mph cited for the Columbus Day Storm.)

[2] From NCDC's ClimVis Database.

[3] The Seattle Naval Air Station (decomissioned in 1970) recorded a
peak gust of 66 mph in the Columbus Day Storm, according to the NCDC's ClimVis
Database.

Table 5 provided a straightforward comparison, however, study of the units-of-measure,
and sensor location information, show that the data from the two storms
were not collected in the same manner, rendering comparisons dubious. Table
6, below, shows winds at some of the above stations, and the
associated instrument information, such as sensor height and location. Differences
between 1962 and 1995 are significant.

Peak Winds, October 12, 1962 and Instrument Data

Location

Peak Wind

Measure

Peak Gust

Measure

Sensor Hgt

Sensor Location

SFO

50

1-Min

63

Instant

20 feet

Field

EUG

63

1-Min

86

Instant

20 feet

Field

SLE

58

1-Min

90

Instant

20 feet

Field

PDX

88

Fast Mi

104

Estimated

33 feet

Field

AST

44

1-Min

96

Instant

46 feet

Field

OLM

58

1-Min

78

Instant

20 feet

Field

SEA

44

1-Min

58

Instant

20 feet

Field

TTI

66

Fast Mi

78

Instant

64 feet

Peak Winds, December 12, 1995 and Instrument Data

Location

Peak Wind

Measure

Peak Gust

Measure

Sensor Hgt

Sensor Location in Relation To 1962 Readings

SFO

54

2-Min

74

Instant

33 feet

Moved 2400 feet SE, Field

EUG

40

2-Min

49

5-Sec

ASOS

Moved, Field

SLE

46

2-Min

59

5-Sec

ASOS

Field

PDX

51

2-Min

62

5-Sec

ASOS

Moved, Elevation Raised 200', Field

AST

46

2-Min

62

5-Sec

ASOS

Field

OLM

45

2-Min

57

5-Sec

ASOS

Field

SEA

37

2-Min

60

Instant

20 feet

Moved 2800 feet SW, Field

TTI

51

2-Min

61

5-sec

83 feet

C-MAN Station (DACT)

With the exception of some stations in Washington, wind speeds for the
December 1995 storm were measured on the new ASOS/AWOS system, which provides
wind data in a 2-minute average format with 5-second peak gust. The ASOS
User's Guide states specifically that, "In ASOS, the peak wind is determined
from the highest 5-second average wind speed that exceeds 25 knots since
the last generated METAR." At the time of the Columbus Day Storm, the
Weather Bureau recorded either average 1-minute winds and/or fastest mile,
with peak instantaneous gust. For example, in the October 1962 Local Climatological
Data for the Eugene airport, the peak wind is listed under fastest 1-minute,
and it is noted that, "a momentary gust of 86 MPH [was] observed."
Further complicating matters, however, is the old method of computing average
wind, which, as noted in the discussion of wind speeds for November
14, 1981, has the possibility of observer error.

Observer error may explain some of the wide variation between peak 1-minute
wind and peak instantaneous gust recorded at some sites in the Columbus
Day Storm. Note the 44 mph gusting to 58 at Sea-Tac and the 44 mph gusting
to 96 at Astoria. It is possible that Astoria's actual peak 1-minute wind
was higher than 44 mph--though the Columbus Day Storm was noted for extremely
gusty winds, as corroborated by a 26 mph gusting to 81 reading at North
Bend. It's probably telling that, on the standard Surface Observation Form
used at the time of the Columbus Day Storm, the wording is such: "Fastest
observed 1-minute wind speed ______ m. p. h. [Emphasis added]"
This is one area where ASOS shines: wind measure is controlled by computer,
which makes the methodology between stations consistent.

If ASOS and AWOS stations provided a 1-minute average and instantaneous
peak gust, these readings would tend to be higher than the new standard
2-minute average and 5-second peak. This means that the reported speeds
for the 1995 storm are probably low when compared to the figures for the
Columbus Day Storm. In an example from my own records, the February 7, 2002
South Valley windstorm produced a peak instantaneous gust of 27 mph on a
new, well-calibrated anemometer. I videotaped the event, and later captured
the footage on computer so that wind velocity in 0.5-second increments could
be recorded. The data are shown in Figure 3, below. From this
data, a running 5-second average was calculated. At 21 mph, the 5-second
peak was much lower than the instant gust. That's a difference of 23%! Figure
3 clearly shows the "smoothing" effect that a 5-second running
mean has on peak instant gusts. The average difference between the instant
reading and the 5-second reading was 1.68 mph for this four-minute stretch
of wind. With an average velocity of 11.38 mph over the four minutes, the
average difference was 15%. Running averages for 30, 60 and 120 seconds
were also calculated. Wind speed lowered for each time interval, though
the difference is less between the longer time-periods. The peak one and
two minute averages were quite close: 14.0 mph and 13.3, or within 5%.

The peak instantaneous gust reported on December 12, 1995 for Portland,
74 mph, was taken on the old pre-ASOS wind gauge, and is therefore an instant
(though now unoffical) reading [personal communication with Dave Willson,
Lead Forecaster for NWS Portland, 2002]. With a peak 5-second gust of 62
mph at the Portland ASOS, there's a difference of 17% between the two readings,
which is close to that 23% figure noted above. Averaging the two percentages
and taking off with this "peak gust adjustment," the 5-second
peak at Eugene converts to an instantaneous gust of 59 mph. Salem changes
to 71 mph, and Astoria to 75. These are still significantly lower than the
storm of '62, but not as much as the new National Weather Service wind measure
format might suggest. A difference of 5% doesn't change the 2-minute averages
much, keeping some of the 1962 readings significantly on top. Due to its
high velocity, Portland's fastest mile of 88 mph in 1962 can be read as
a 41-second average (essentially, wind moving at 88 mph will cover a mile
in 41 seconds). In the wind data I took for the 2002 storm, the difference
between the 41-second and 2-minute averages is about 15%. Portland's peak
2-minute wind of 51 mph for the December 1995 storm converts to a 59 mph
41-second speed, still far off the 1962 mark--that's a difference in wind
force of about 2.2 times.

There are many objections to these adjustments, not the least of which
is that the anemometer used for the conversions is of a different make than
an ASOS wind sensor. With a difference of about 40% between peak 5-second
and peak 2-minute, it is clear that the winds at my location were significantly
more turbulent than at less obstructed airport-based anemometers, which
usually vary between 15% and 25% between average speed and gust. And the
sample resolution of 0.5 second is also probably different. The above paragraph
mainly serves to show what potential differences might exist between the
two formats. The average difference between peak gust and peak 5-second
wind at ASOS stations is probably more like 5-10% by conservative estimate.

Unfortunately, changes in wind record format aren't the only complications
introduced when comparing wind speeds between the two storms. Modern ASOS
wind sensors tend to be higher than the 20-foot standard of the pre-automated
era. According to the ASOS User's Guide, Most ASOS anemometers are put at
the new FAA standard of 10 meters, or 32.8 feet, with some at 27 feet, depending
on "site-specific restrictions or requirements." Anyone who's
played around with setting up an anemometer knows that a relatively small
increase in height can have a significant affect on peak winds. A change
of 7-13 feet is 25-40% higher than the old 20-foot standard. Wind speeds
will tend to be higher with the new system. This, in effect, means that
the adjusted peak gusts are probably high in comparison to the Columbus
Day Storm, with a few exceptions, like Astoria, where the anemometer has
been lowered to meet the new standard.

Ultimately, what is left after this analysis is a fairly muddy comparison
that suggests the Columbus Day Storm had more powerful winds, at least at
most Oregon locations. There is some evidence in the data that suggest the
1995 event was somewhat of a flip-flop of the 1962 one, with the strongest
impact happening in Northern California, then again in the Seattle Area.
The peak 5-second wind of 74 mph at San Francisco shines far above the 62
mph instantaneous gust in 1962, and Sea-Tac's pathetic 58 mph for the Columbus
Day Storm is a mark below the 60 recorded in 1995. Despite well-calibrated
anemometers set up at many locations, it seems that, like for the January
1880 cyclone, anecdotal evidence is still king when comparing windstorms!
Comparison of the newspaper accounts, and personal experiences, suggest
rather unanimously that, even though December 1995 was bad, the level of
emergency that resulted during the 1962 Big Blow was far, far worse.

Table 7, below, shows the December 12, 1995 windstorm's
peak wind and gust for the stations in Table 6, adjusted to reflect the
differences in sensor height and wind measure. Note that the power law formula
was intended for sustained winds, not wind gusts, so its application in
the peak gust column is a bit dubious.

These adjusted December 12, 1995 peak wind values can then be compared to
the Columbus Day Storm, as is done in Table 8, below. A positive
value in the difference column reflects stronger winds during the 1962 event,
negative reflects stronger winds during the 1995 event. The results put
the Columbus Day Storm clearly on top for many places in Oregon. December
1995 has the edge over the 1962 storm far south in San Francisco, and in
the Seattle area--but the difference is minor compared to the Columbus Day
Storm's huge margin in places like the Willamette Valley. The Columbus Day
Storm's lead narrows northward, indicative of the 1962 cyclone's weakening
off the Washington Coast more than a significantly larger 1995 impact for
Washington.

Adjusted Peak Winds for December 1995
Compared to Peak Winds for October 1962

Location

Peak Wind
Oct 1962
mph

Peak Wind
Dec 1995
mph

Difference
mph

Peak Gust
Oct 1962

Peak Gust
Dec 1995

Difference
mph

SFO

50

53

-3

63

69

-6

EUG

63

39

24

86

50

36

SLE

58

45

13

90

60

30

PDX

63

54

9

104

68

36

AST

44

51

-7

96

72

24

OLM

58

44

14

78

58

20

SEA

44

39

5

58

60

-2

TTI

49

52

-3

78

65

13

With the differences in wind measure now noted, the discussion can now move
to Table 9, below, a list of the peak wind and gust for eleven
key stations in the Pacific Northwest, their direction, and their time of
occurrence. By my own personal methodology, a wind event rates the term
"windstorm" when the average peak gust of these eleven stations
reaches 39.0 mph (gale force) or higher. This ranking favors those storms
that follow a northward path close to the U.S. Pacific Coast, and for good
reason--such storms affect the largest land area, and therefore are potentially
the most destructive. The incredibly deep December 12, 1995 cyclone followed
such a path, with damaging, sometimes outright destructive, winds striking
many points along the way, and this windstorm's average peak gust, 61.4
mph, ranks this event among the few great storms of history. Taken without
modification for difference in wind measure, the 1995 strom is behind just
three storms from the 1950-to-present era: January 15, 1951 with an average
of 61.6 mph, October 12, 1962 with an average of 80.5, and November 14,
1981 with an average of 65.9. With a conservative 10% adjustment upward
for peak gusts at known ASOS stations, the December 1995 storm shows an
average peak of 64.4, which places it 3rd behind the November 14, 1981 and
Columbus Day Storms. That's a close 3rd, and it could very well have edged
second with an unusually high peak instant gust at a station or two.

Location

Peak
Windmph

Direction
Pk Wnddegrees

Obs Time of
Peak WindPST

Peak
Gustmph

Direction
Pk Gstdegrees

Obs Time of
Peak GustPST

California:

Arcata

35

220º

07:53 HRS, 12th

58

220º

07:42 HRS, 12th

Oregon:

North Bend [1]

69

180º

11:49 HRS, 12th

86

180º

11:49 HRS, 12th

Astoria

46

200º

17:57 HRS, 12th

62

190º

17:56 HRS, 12th

Medford [2]

31

150º

MM

45

140º

MM

Eugene

40

180º

13:02 HRS, 12th

49

180º

13:01 HRS, 12th

Salem

46

170º

13:23 HRS, 12th

59

180º

13:23 HRS, 12th

Portland

51

170º

13:17 HRS, 12th

62

170º

14:20 HRS, 12th

Washington:

Quillayute [3]

51

237º

22:00 HRS, 12th

61

237º

22:00 HRS, 12th

Olympia

45

160º

14:41 HRS, 12th

57

140º

14:48 HRS, 12th

Sea-Tac [4]

37

180º

19:00 HRS, 12th

60

180º

MM

Bellingham

37

190º

23:58 HRS, 12th

76

200º

22:34 HRS, 12th

AVERAGE [5]

44.4

185º

61.4

183º

Table 9, notes.

[1] Due to equipment failure during the storm, possibly due to power
failure, wind direction at North Bend was estimated at the time of peak
winds. Its probable that the peak velocities were also estimates, but this
isn't clear on the surface observation form.

[2] Medford's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Wind data are from the Local Climatological Data
monthly summary for December 1995. Time of peak wind and gust not noted
in the publication.

[3] Quillayute's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Quillayute's peak gust not noted on the December
1995 Local Climatological Data montly summary. Tatoosh Island C-MAN station
TTIW used in place of Quillayute. Incidentially, this makes for more accurate
comparisons between this storm and those before the 1964 opening year for
the Quillayute station, which replaced the Tatoosh station for many decades.
And it also probably gives a boost to the 11-station averages, for winds
at Tatoosh tend to be higher than at Quillayute.

[4] Sea-Tac's unedited surface observation forms lost due to a corrupt
data file at the NCDC. Peak wind is from the 3-hourly observations noted
in the Local Climatological Data monthly summary for Sea-Tac, December 1995,
as is peak gust.

[5] Assumes 5-second and instant gusts are the same.

Table 10, below, lists the peak gusts reported by NWS Seattle
spotters (with a few from Oregon) during the December 12,1995 windstorm.
These reports were posted during the storm by NWS Seattle, and I carefully
collected them all as they became available. Taken at face value, some of
these peaks approached Columbus Day Storm levels, and in the storm reports
it is mentioned that 60 to 80 mph readings were also seen in the Willamette
Valley of Oregon. However, it is interesting that the higher winds managed
to miss many official stations in Dec 1995--though the difference in wind
measure, 5-second peak next to peak instant gust, may account for some of
the disparity. With few exceptions during the Columbus Day Storm, the official
stations were slammed just as hard as the unofficial ones (indeed, a number
of official sites had instrument failure due to power outages and/or structural
damage!). The Sea-Tac Airport is the one big exception. Despite a 100 mph
reading at the nearby Renton Airport, Sea-Tac only managed a peak of 58
mph in 1962 (note that the anemometer at Renton was at 64' above ground
level, fully 44' above SeaTac's 20'). Sea-Tac's reading is so much lower
than the typical 75-95 mph gusts in the region that it is unusual.
It should be noted that some of the locations below are more wind prone
than official sites. I've seen Auburn yield high readings in windstorms
previous to December 1995, such as 70 mph during the January 16, 1986 storm,
so a high reading at this location my not be that unusual for a storm of
this type. Enumclaw typically gets strong east winds ahead of deep, NE-trending
storms. Portland, OR, sees a similar effect as winds rush down the Columbia
River Gorge.

Location

Peak Wind

Time

Enumclaw, WA

60 mph (E)

6:00 AM

Wickersham, WA

50 mph

8:00 AM

Alsea, OR (Near Corvallis)

70 mph

11:30 AM

Sea Lion Caves, OR

118 mph

12:00 PM

Chinook, WA

78 mph

1:30 PM

Puyallup, WA (Pierce 6)

65 mph (SE)

2:00 PM

Grayland Beach, WA (Grasy Harbor 2)

50 mph

2:20 PM

Ocean Shores, WA (Grays Harbor 5)

54 mph

2:30 PM

Seattle, WA (King 23)

40 mph

2:45 PM

Ocean Shores, WA (Grays Harbor 5)

54 mph

5:00 PM

Mukilteo, WA (Snohomish 30)

58 mph

6:00 PM

Tacoma, WA (Pierce 20)

56 mph

6:20 PM

Seattle, WA (King 23)

51 mph

6:20 PM

Marysville, WA

46 mph

6:20 PM

Auburn, WA

70 mph

6:30 PM

Olympia, WA (Thurston 1)

65 mph

6:30 PM

Long Beach, WA

61 mph

6:50 PM

Harbor Island, Seattle, WA

78 mph

7:40 PM

Aberdeen, WA (Grays Harbor 10H)

55 mph

7:47 PM

Lummi Island, WA

50 mph

7:50 PM

Edmonds, WA

64 mph

8:20 PM

Mukilteo, WA (Snohomish 30)

86 mph

8:20 PM

North Bend, WA

78 mph

8:20 PM

Bellingham, WA (Whatcom 8)

54 mph (S)

8:40 PM

Marysville, WA (Snohomish 35)

55 mph (SE)

8:40 PM

Table 11, below, lists some storm reports posted by the NWS
at Monterey during the December 12, 1995 windstorm. Some of the rainfall
readings are truly spectacular. For comparison to the Columbus Day Storm:
San Francisco reported a 3-day rain total of 4.78" by 3 PM Saturday,
October 13, 1962, which brought the season total (starting July 1st) to
5.09", which was the second highest in 113 years of record (1904 saw
7.12" by Oct 13th). The Oakland International Airport was soaked with
4.32" of rain in 24 hours. Woodside had 9.59" during the Columbus
Day Storm, Skylonda 8.07" in 24 hours, and Belmont had 4.47" in
24 hours. Yreka saw 4.97" in six days. It seems that in the rain department,
as with the peak gusts, December 1995 surpassed the Columbus Day Storm at
some locations.

8.98" storm total rainfall. Many downed trees and widespread power
outages.

10:00 AM

Belmont, CA (San Mateo Co.)

62 mph wind gust. 4.5" storm total rainfall.

10:30 AM

San Francisco, CA (San Francisco Co.)

Large sinkhole affected 25 families.

10:50 AM

Healdsburg, CA (Sonoma Co.)

15.01" storm total rainfall at Russian River. Numerous power lines
and trees down.

1:00 PM

Cambria, CA (San Luis Obispo Co.)

8.0" rainfall from 8:00 AM to 1:15 PM.

1:25 PM

San Francisco, CA, Conservatory

10 million dollars damage due to structural failure, broken windows and
plants destroyed.

4:00 PM

This is what John Monteverdi, Meteorologist at San Francisco State University,
wrote on December 15, 1995 as he introduced a new website dedicated to the
December 12, 1995 windstorm:

"In case some people had not heard, peak winds in the SF Bay Region
included 103 mph on Angel Island (sea level), 85 mph at San Francisco State
University (100 ft, 3/4 mile inland) and 139 mph in the Diablo Range east
of San Francisco. Rainfall totals included 5.56 at SFSU, 7.54 at Santa Rosa
and over 15 inches in Ross. Some evidence of possible wet microburst-related
damage in southwestern SF. Most portions of southwestern SF look like a
hurricane swept through (of course, you say, these were hurricane
force winds)."

[Italics mine.]

California Rainfall

Table 12, below, a version of which appeared in the Oakland
Tribune, shows the storm total rainfall of the December 1995 winstorm
compared to the season total for 1995-96 (which begins on June 1st in California)
as of December 12, 1995. The percentages are high, reflecting a very dry
autumn up to the time of the big storm. Had the tempest struck at a time
of more normal precipitation, then the flood damage from the heavy rainfall
totals of Dec 12 would probably have been worse. Original source of the
data: AccuWeather.